| 摘要 |
A soft permeable material, such as a foamed plastics material or a fibrous material is shaped, and optionally provided with one or more facing layers, by applying to the faces thereof a polyurethane based prepolymer composition under such conditions that a non-tacky coating having latent adhesive properties is formed. The coated material may be stored for a period of several months and subsequently shaped by the application of heat and pressure sufficient to cure the pre-polymer. Facing layers can be bonded thereto simultaneously without the application of additional adhesive substance. The latent adhesive substance may be applied to the permeable material in solution or in the form of a dry film. In the latter case the film may be applied initially to a facing layer. The latent adhesive substance may be used to form reclaimed waste material into a coherent mass which can subsequently be shaped and faced without the application of further adhesive substance. |
